The invention relates to an apparatus for preparing a number of consumption units of a beverage, such as coffee or tea, comprising a beverage making apparatus with water supply means, a filterpan and a disposable filter cartridge that fits into the filterpan, the filterpan and filter cartridge having cooperating parts for forming a watertight seal, and a support surface being provided for a vessel for receiving the extract.
In such an apparatus, essentially all of the water must be passed through the central portion of the filter if all of the water is to properly participate in the brewing process. If, instead, some of the water flows away at the sides via the route of least resistance, all of the water will not or will not participate sufficiently in the brewing process.
An apparatus which addresses this problem is disclosed in German Auslegeschrift 3.613.119 and the corresponding European patent application 249,700. To ensure that all of the water passes through the filter at the proper location, this apparatus makes use of the effect of the degassing of the coffee. This creates a minor excess pressure in the space within the filter cartridge. As a result, the upper surface of the filter will bulge in such a way that this surface engages the downwardly directed, suspending circular edge of a partition along the inner side of which the heated water is supplied.
This requires very accurate dimensioning to ensure that sufficient bulging occurs. Accordingly, only specially shaped filters, in which the material to be extracted is uniformly distributed can be used. Nevertheless, before the bulging takes place, a part of the water will freely flow away at the sides and thus participates insufficiently in the brewing process.
The present invention is directed to this problem. To solve this problem, the apparatus of the present invention has a filterpan ring, i.e., the water outflow part, which ensures that all of the water reaches the filter.
The filterpan ring may be connected to the filterpan for pivoting movement.
In one embodiment of the invention, the water supply rate may be higher than the discharge rate of the extract. It will be clear that, in that case, the volume of the part of the filterpan that is external relatively to the outflow part must be sufficiently large to receive the excess water.
By providing an opening at the top of the water outflow part, the build-up of too large a pressure in the water outflow part, and hence the chance of accidents happening, is avoided.